U.S. patent application number 13/431178 was filed with the patent office on 2012-12-27 for additive dispensing filter and method.
This patent application is currently assigned to FRAM GROUP IP, LLC. Invention is credited to Donald William Baldwin, JR..
Application Number | 20120325752 13/431178 |
Document ID | / |
Family ID | 47360844 |
Filed Date | 2012-12-27 |
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United States Patent
Application |
20120325752 |
Kind Code |
A1 |
Baldwin, JR.; Donald
William |
December 27, 2012 |
ADDITIVE DISPENSING FILTER AND METHOD
Abstract
An additive cartridge for dispersing an additive within a filter
housing is provided. The additive cartridge includes an additive
cartridge housing having a peripheral wall, the additive cartridge
housing defining first interior area and a second interior area
being divided by a first wall. A first unidirectional fluid path is
disposed adjacent the second end, the first fluid path defining a
flow path from the second interior area. A first biasing member
being made from a shape-memory alloy disposed in the second
interior area adjacent the first end, the shape memory alloy moving
between a first position and a second position in response to a
change in temperature. A first piston member is movably disposed
within the second interior area and coupled to the first biasing
member, the first piston member defining a dispensing chamber
within the second interior area.
Inventors: |
Baldwin, JR.; Donald William;
(Perrysburg, OH) |
Assignee: |
FRAM GROUP IP, LLC
Lake Forest
IL
|
Family ID: |
47360844 |
Appl. No.: |
13/431178 |
Filed: |
March 27, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61500317 |
Jun 23, 2011 |
|
|
|
Current U.S.
Class: |
210/742 ;
210/149; 222/387; 222/54 |
Current CPC
Class: |
B01D 27/06 20130101;
B01D 35/153 20130101; B01D 37/025 20130101 |
Class at
Publication: |
210/742 ; 222/54;
222/387; 210/149 |
International
Class: |
B01D 35/30 20060101
B01D035/30; B01D 35/02 20060101 B01D035/02; B05C 17/01 20060101
B05C017/01 |
Claims
1. An additive cartridge for dispersing an additive within a filter
housing, the additive cartridge comprising: an additive cartridge
housing having a peripheral wall, the additive cartridge housing
defining a first interior area and a second interior area being
divided by a first wall, the first interior area defining a
receiving area for receipt of the additive therein, the second
interior area having a first end and a second end; a first fluid
path disposed adjacent the second end, the first fluid path
defining a flow path from the second interior area, the first fluid
path configured to allow unidirectional flow from the second
interior area through the peripheral wall; a first biasing member
made from a shape memory alloy disposed in the second interior area
adjacent the first end, the shape memory alloy moving between a
first position and a second position in response to a change in
temperature; and, a first piston member movably disposed within the
second interior area and coupled to the first biasing member, the
first piston member defining a dispensing chamber within the second
interior area.
2. The additive cartridge of claim 1 further comprising a second
fluid path between the first interior area and the second interior
area, the first fluid path configured to allow unidirectional flow
of the additive from the first interior to the second interior
area.
3. The additive cartridge of claim 1 wherein the first biasing
member is in the first position at a first temperature and in the
second position at a second temperature.
4. The additive cartridge of claim 3 wherein the first temperature
is a temperature equal to or less than 130 F and the second
temperature is a temperature equal to or greater than 150 F.
5. The additive cartridge of claim 3 wherein the shape memory alloy
is selected from a group comprising: a Cu--Zn--Al--Ni alloy, a
Cu--Al--Ni alloy and a Ni--Ti alloy.
6. The additive cartridge of claim 1 further comprising: a second
biasing member made from a shape-memory alloy disposed in the
second interior area between the first fluid path and the second
end, the shape memory alloy moving between a third position and a
fourth position in response to a change in temperature; and, a
second piston member movably disposed within the second interior
area and coupled to the second biasing member.
7. A filter comprising: a filter housing defining an inlet fluid
opening and an outlet fluid opening, the inlet fluid opening and
the outlet fluid opening defining a first fluid path through the
filter; a filter element disposed inside the filter housing, the
filter element being disposed in the first fluid path such that
fluid flows through the filter element; and an additive cartridge
for dispersing an additive within the filter housing, the additive
cartridge comprising: an additive cartridge housing having an outer
peripheral wall, the additive cartridge housing defining a first
interior area and a second interior area divided by a first wall,
the second interior area having a first end and a second end; a
second fluid path disposed within the second interior area, the
second fluid path defining a flow path from the second interior
area through the outer peripheral wall to the first fluid path, the
second fluid path configured to allow unidirectional flow from the
second interior area through the outer peripheral wall; a first
biasing member made from a shape memory alloy disposed in the
second interior area adjacent the first end, the shape memory alloy
moving between a first position and a second position in response
to a change in temperature; and, a first piston member movably
disposed within the second interior area and coupled to the first
biasing member, the first piston member defining a dispensing
chamber within the second interior area.
8. The filter of claim 7 wherein the second fluid path is fluidly
coupled to the first fluid path between the filter element and the
outlet fluid opening.
9. The filter of claim 8 wherein the first biasing member is in the
first position at a first temperature and in the second position at
a second temperature.
10. The additive cartridge of claim 9 wherein the first temperature
is a temperature equal to or less than 130 F and the second
temperature is a temperature equal to or greater than 150 F.
11. The additive cartridge of claim 10 further comprising a third
fluid path between the first interior area and the second interior
area, the third fluid path configured to allow unidirectional flow
from the first interior area to the second interior area.
12. The additive cartridge of claim 11 further comprising: a first
check valve disposed in the second fluid path, the first check
valve being configured to allow uni-directional flow of additive
from the dispensing chamber to the first fluid path; and, a second
check valve disposed in the third fluid path, the second check
valve being configured to allow uni-directional flow of additive
from the first interior area to the dispensing chamber.
13. The additive cartridge of claim 7 further comprising: a second
biasing member made from a shape-memory alloy disposed in the
second interior area adjacent the second end, the shape memory
alloy moving between a third position and a fourth position in
response to a change in temperature; and, a second piston member
movably disposed within the second interior area and coupled to the
second biasing member.
14. A method for dispersing an additive from an oil filter, the
method comprising: providing an additive cartridge having a first
interior area and a second interior area; providing a first biasing
member in the second interior area, the first biasing member being
made from a shape memory alloy; heating the first biasing member
from a first temperature to a second temperature; moving the first
biasing member from a first position to a second position in
response to the heating; flowing additive from the second interior
area to through a peripheral wall of the additive cartridge as the
first biasing member moves from the first position to the second
position; cooling the first biasing member to the first
temperature; moving the first biasing member from the second
position to the first position in response to the cooling; flowing
the additive from the first interior area to the second interior
area as the first biasing member moves from the second position to
the first position.
15. The method of claim 14 further comprising preventing flow of
additive from the second interior area to the first interior area
when flowing the additive from the second interior area through the
peripheral wall.
16. The method of claim 15 further comprising preventing fluid flow
through the peripheral wall to the second interior area when
flowing the additive from the first interior area to the second
interior area.
17. The method of claim 16 further comprising: providing a second
biasing member in the second interior area, the second biasing
member made from a shape memory alloy; heating the second biasing
member; moving the second biasing member from a third position to a
fourth position in response to the hearing of the second biasing
member; and, flowing additive from the second interior area through
the peripheral wall as the second biasing member moves from the
third position to the fourth position;
18. The method of claim 17 further comprising: cooling the second
biasing member; moving the second biasing member from the fourth
position to the third position; and, flowing additive from the
first interior area to the second interior area as the second
biasing member moves from the fourth position to the third
position.
19. The method of claim 18 wherein the additive composition
comprises at least one additive selected from a group consisting of
basic conditioners, corrosion inhibitors, metal deactivators,
antioxidants, dispersants, friction modifiers, oil stabilizers,
pour point depressants, detergents, viscosity index improvers,
anti-wear agents, extreme pressure additives, and mixtures thereof
and the additive composition is a liquid.
20. The method of claim 18 wherein the additive composition
comprises a basic salt selected from a group consisting of calcium
carbonate, potassium carbonate, potassium bicarbonate, aluminum
dihydroxy sodium carbonate, magnesium oxide, magnesium carbonate,
zinc oxide, sodium bicarbonate, sodium hydroxide, calcium
hydroxide, potassium hydroxide, and mixtures thereof and the
additive composition is a liquid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional patent application
which claims the benefit of U.S. Provisional Patent Application No.
61/500,317 filed Jun. 23, 2011, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The subject matter disclosed herein relates to an additive
dispersing filter and method of dispersing an additive to a fluid
passing through a filter.
[0003] Many different types of fluid filters are known. Most such
filters use a mechanical or `screening` type of filtration, with a
porous filter element disposed therein. The oil is repeatedly
cycled through the filter element to remove impurities.
[0004] In the oil filtration art, it is well known that normal
operation of an internal combustion engine, particularly a diesel
engine, results in the formation of contaminants. These
contaminants include, among others, soot, which is formed from
incomplete combustion of the fossil fuel, and acids that result
from combustion. These contaminants are typically introduced into
the lubricating oil during engine operation, and tend to increase
oil viscosity and generate unwanted engine deposits, leading to
increased engine wear.
[0005] The conventional solution to these problems has been to
place various additives into lubricating oils, during their initial
formulation. To combat soot-related problems, many conventional
lubricating oils include dispersants that resist agglomeration of
soot therein. These work well for a short period, but may become
depleted. Additionally, due to the solubility and chemical
stability limits of these dispersants in the oil, the service lives
of the lubricating oil and the oil filter are less than
optimal.
[0006] To counteract the effects of acidic combustion products,
many conventional motor oils include neutralizing additives known
as over-based detergents. These are a source of TBN (total base
number), which is a measure of the quantity of the over-based
detergent in the oil. The depletion of the TBN is an important
limiting factor for many internal combustion engines, particularly
for heavy-duty applications with diesel engines.
[0007] To improve engine protection and to combat other problems,
conventional lubricating oils often include one or more further
additives, which may be corrosion inhibitors, antioxidants,
friction modifiers, pour point depressants, detergents, viscosity
index improvers, anti-wear agents, and/or extreme pressure
additives. While the inclusion of these further additives may be
beneficial, the amount and concentration of these additives, using
conventional methods, are limited by the ability of lubricating
oils to suspend these additives, as well as by the chemical
stability of these additives in the oil.
[0008] While the known filters are usable for their intended
purposes, the release of supplemental additives from the known
filters often takes place either immediately after installation or
more rapidly than is needed for protecting the oil. Subsequently,
after some time has elapsed, there may be little or no additive
left in the filter.
[0009] Another problem with many of the known filter designs is
that beneficial additives are added to the oil before the oil is
mechanically filtered through a filter element. As a result, when
the oil is mechanically filtered, some of the beneficial additives
that have just been added may be immediately filtered out.
[0010] Moreover, recent emission regulations require heavy/medium
duty diesel engines to run at conditions that deteriorate the crank
case lube oil additive package at an accelerated rate. This leads
to a reduction in the number of miles a truck can travel before the
crank case oil needs to be changed, causing increase in downtime
and operating costs of the truck, and thus reducing profits for the
owner.
[0011] Therefore it is desirable to provide a filter having an
additive incorporated therein, wherein the additive is slowly
released over the useful life of the filter. It is also desirable
to provide an oil filter which could extend the useful life of
engine oil so as to allow a user to extend the time interval
between oil changes of an engine.
BRIEF DESCRIPTION OF THE INVENTION
[0012] According to one aspect of the invention, an additive
cartridge for dispersing an additive within a filter housing is
provided. The additive cartridge includes an additive cartridge
housing having a peripheral wall, the additive cartridge housing
defining first interior area and a second interior area being
divided by a first wall, the first interior area defining a
receiving area for receipt of the additive therein, the second
interior area having a first end and a second end. A first fluid
path is disposed adjacent the second end, the first fluid path
defining a flow path from the second interior area, the second
fluid path configured to allow unidirectional flow from the second
interior area through the peripheral wall. A first biasing member
is made from a shape-memory alloy disposed in the second interior
area adjacent the first end, the shape memory alloy moving between
a first position and a second position in response to a change in
temperature. A first piston member is movably disposed within the
second interior area and coupled to the first biasing member, the
first piston member defining a dispensing chamber within the second
interior area.
[0013] According to another aspect of the invention, a filter is
provided. The filter includes a housing defining an inlet fluid
opening and an outlet fluid opening, the inlet fluid opening and
the outlet fluid opening defining a first fluid path through the
filter. A filter element is disposed inside the filter housing, the
filter element being disposed in the first flow path such that
fluid flows through the filter element. An additive cartridge is
arranged for dispersing an additive within a filter housing, the
additive cartridge includes an additive cartridge housing having a
peripheral wall, the additive cartridge housing defining first
interior area and a second interior area divided by a first wall,
the second interior area having a first end and a second end. A
first fluid path is disposed within the second interior area, the
first fluid path defining a flow path from the second interior area
through the outer peripheral wall to the first flow path, the first
fluid path configured to allow unidirectional flow from the second
interior area through the peripheral wall. A first biasing member
is made from a shape-memory alloy disposed in the second interior
area adjacent the first end, the shape memory allow moving between
a first position and a second position in response to a change in
temperature. A first piston member is movably disposed within the
second interior area and coupled to the biasing member, the first
piston member defining a dispensing chamber within the second
interior area.
[0014] According to yet another aspect of the invention, a method
for dispersing an additive from an additive cartridge disposed in a
housing of an oil filter is provided. The method includes providing
an additive cartridge having a first interior area and a second
interior area. A first biasing member is provided in the second
interior area, the first biasing member being made from a shape
memory alloy. The first biasing member is heated from a first
temperature to a second temperature. The first biasing member is
moved from a first position to a second position in response to the
heating. The additive flows from the second interior area to
through a peripheral wall of the additive cartridge as the first
biasing member moves from the first position to the second
position. The first biasing member is cooled to the first
temperature. The first biasing member is moved from the second
position to the first position in response to the cooling. The
additive flows from the first interior area to the second interior
area as the first biasing member moves from the second position to
the first position.
[0015] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0016] The subject matter, which is regarded as the invention, is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0017] FIG. 1 is a perspective view of an oil filter constructed in
accordance with an exemplary embodiment of the invention;
[0018] FIG. 2 is a side sectional view of the oil filter of FIG. 1
in accordance with one embodiment of the invention;
[0019] FIG. 3 is a side sectional view of the oil filter of FIG. 1
in accordance with another embodiment of the invention;
[0020] FIGS. 4-6 are side schematic views of an additive cartridge
for use with the oil filter of FIG. 1; and,
[0021] FIG. 7 is a side schematic view of another additive
cartridge for use with the oil filter of FIG. 1.
[0022] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Embodiments of the present invention provide advantages in
dispersing an additive composition into oil, such as motor oil to
increase the service life of the oil. Embodiments described herein
provide for an additive dispersion cartridge that injects oil into
an oil flow path within an oil filter where the additive compound
is injected once per engine heating cycle. The additive cartridge
has a temperature driven piston arrangement that disperses a
metered amount of additive compound when the engine oil achieves a
desired temperature level. The piston arrangement includes a
biasing member made from a shape memory alloy that moves between an
compressed position and an extended position. The piston
arrangement further includes a valve arrangement that allows the
additive compound to be flowed from a reservoir when the engine
cools and dispersed to the oil upon the heating of the engine to a
desired level.
[0024] The present application is related to the following patent
applications, the contents each of which are incorporated herein by
reference thereto: Ser. No. 10/352,344, filed Jan. 27, 2003; Ser.
No. 09/867,973, filed May 30, 2001; Ser. No. 09/566,034 filed May
8, 2000; U.S. patent application Ser. No. 10/863,581, filed Jun. 8,
2004; U.S. patent application Ser. No. 11/488,466, filed Jul. 18,
2006; U.S. patent application Ser. No. 11/533,649 filed Sep. 20,
2006; U.S. patent application Ser. No. 11/845,042, filed Aug. 25,
2007; U.S. patent application Ser. No. 11/845,043, filed Aug. 25,
2007; U.S. patent application Ser. No. 11/846,265, filed Aug. 28,
2007; U.S. provisional patent application Ser. No. 60/889,728,
filed Feb. 13, 2007; U.S. provisional patent application Ser. No.
60/910,772 filed Apr. 9, 2007; U.S. provisional patent application
Ser. No. 60/985,193 filed Nov. 2, 2007, U.S. patent application
Ser. No. 12/030,595 filed Feb. 13, 2008, and U.S. patent
application Ser. No. 12/032,241 filed Feb. 15, 2008 the contents
each of which are incorporated herein by reference thereto.
[0025] Referring to FIG. 1 and FIG. 2, there is shown an oil filter
10 in accordance with an embodiment of the invention. The oil
filter 10 generally includes a hollow cylindrical housing 12 which
defines a hollow interior chamber 14. A mechanical filter medium 18
is disposed within that chamber along with an additive cartridge 20
arranged on one end. The housing 12 may also include a tapping pate
24 that is sealingly coupled to the housing 12. In some
embodiments, a center tube may optionally be provided within the
filter housing to support and reinforce the mechanical filter
element 18.
[0026] In the exemplary embodiment, the filter element 18 is a
conventional cylindrical member made of accordion-pleated filter
paper. In other embodiments, the filter element 18 may be
manufactured in accordance with the teachings of U.S. patent
application Ser. No. 11/533,649 filed Sep. 20, 2006 or U.S.
application Ser. No. 11/845,042 filed Aug. 25, 2006, the contents
of each being incorporated herein by reference in their
entirety.
[0027] The tapping plate 24 may include a number of inlet ports 32
arranged in a circular pattern. The tapping plate also includes an
outlet port 34. The outlet port has a thread portion that allows
the mounting of the filter 10 on hollow tubular fitting on an
engine block (not shown). An annular seal or gasket 36 is disposed
in a groove formed on the bottom surface of the filter 10 to resist
oil leakage outwardly from the filter 10.
[0028] Referring to FIGS. 2-3, the additive dispensing cartridge 20
includes an outer shell 38 forming a peripheral wall that defines
an interior area 40 for housing a reservoir. The reservoir is sized
to contain a desired amount of an additive dispersant material
suitable for the expected operational life of the filter 10.
Adjacent the inner area 40 is a metering device 42. The metering
device 42 includes a wall 44 that defines another interior area 46,
which contains a biasing member 48, a piston member 50 and a
dispensing chamber 52. As will be discussed in more detail below,
the biasing member 48 is made from a shape memory alloy that allows
the biasing member 48 to change shape and move in response to a
change in temperature. In the exemplary embodiment, the biasing
member 48 may be made from a Cu--Zn--Al--Ni alloy, a Cu--Al--Ni
alloy or a Ni--Ti alloy.
[0029] An inlet valve 54 forms a flow path from the interior area
40 into the dispensing chamber 52. The inlet valve 54 may be a
check valve that only allows the additive to flow in one direction
into the dispensing chamber. An outlet valve 56 forms a flow path
from the dispensing chamber into a center area 58 within the filter
medium 18. The outlet valve 56 is configured to open at a
predetermined pressure within the dispensing chamber 52 and only
allow flow from the dispensing chamber 52 into the center area 58.
The valves 54, 56 may be any suitable check valve, including but
not limited to a ball check valve, a diaphragm check valve, a swing
check valve, a tilting disk check valve, a stop check valve or a
lift check valve, or a combination of the foregoing for
example.
[0030] In one embodiment, shown in FIG. 2, the additive cartridge
20 is disposed adjacent the closed end of the housing 12. In this
embodiment, the additive flows from the additive cartridge 20 into
one end of the center area 58 within the filter medium 18. In
another embodiment, shown in FIG. 3, the additive cartridge 20 is
disposed between the center area 58 and the outlet port 34. In this
embodiment, the interior area 40 forms an annularly-shaped
reservoir with a cylindrical opening 60 that extends through the
shell 38 to allow oil to flow to the outlet port 34. The outlet
valve 56 is arranged to flow the additive into the opening 60.
[0031] It should be appreciated that while embodiments herein
describe the additive cartridge as being internal to the filter 10,
this is for exemplary purposes and the claimed invention should not
be so limited. In other embodiments, the additive cartridge is
external to the filter. Still further, embodiments describe the
additive cartridge as being positioned between the filter medium
and the outlet port. In other embodiments, the additive cartridge
may be positioned in a flow path between the inlet port and the
filter medium.
[0032] The additive cartridge 20 includes an additive material
within the reservoir. The additive 62 (FIG. 4) may be a liquid or
semi-liquid form for being released into the oil flow path. The
additive 62 may be any one of a detergent or dispersant additive
that is configured to suspend particles of soot within the oil,
such that in one embodiment, the oil carries the soot particles to
the filter for removal from the oil. Alternatively, the dispersant
is used to keep the soot in suspension in the oil such that it does
not agglomerate and fall out of suspension and thereby accumulate
on surfaces and potentially cause wear or plugging issues. Other
contemplated beneficial additives are basic conditioners, corrosion
inhibitors, metal deactivators, antioxidants, friction modifiers,
oil stabilizers, pour point depressants, viscosity index improvers,
anti-wear agents, extreme pressure additives, alkaline additives,
and combinations of the foregoing.
[0033] The additive material 62 may also include a basic salt
selected from the group consisting of calcium carbonate, potassium
carbonate, potassium bicarbonate, aluminum dihydroxy sodium
carbonate, magnesium oxide, magnesium carbonate, zinc oxide, sodium
bicarbonate, sodium hydroxide, calcium hydroxide, potassium
hydroxide, and mixtures thereof.
[0034] Referring now to FIGS. 4-6, the operation of the additive
cartridge 20 is described. The interior area 40 is substantially
filled with a desired amount of the additive material 62. When
initially filled, there is little or no pressure differential
across the valve 54 so the additive material 62 will not flow into
the dispensing chamber 52. The piston member 50 and biasing member
48 are in an initial position. It should be appreciated that in
some embodiments, the dispensing chamber 52 may be initially filled
with additive material as well. When the filter 10 is installed on
the desired application, such as an internal combustion engine for
example, the temperature of the additive compartment will increase
as the temperature of the engine increases. In the exemplary
embodiment, the additive cartridge 20 will be at a temperature of
less than 130.degree. F. in a cold state and greater than
150.degree. F. in a operating or hot state.
[0035] As the temperature of the additive cartridge 20 decreases
from an operating temperature (e.g. >150.degree.) to a rest
temperature (e.g. <130.degree. F.), the biasing member 48 and
the attached piston member 50 move from an initial position (FIG.
4) to a compressed or second position (FIG. 5). This movement of
the biasing member 48 increases the size of the dispensing chamber
52 creating a pressure differential across the valve 54. This
pressure differential opens the valve 54 allowing additive material
62 to flow along a first flow path through the valve 54 to
substantially fill the dispensing chamber with additive material 64
(FIG. 5). The next time the engine (or other desired application)
is started, the temperature of the additive cartridge
increases.
[0036] When the operating temperature of the environment causes the
cartridge temperature to exceed a predetermined threshold (e.g.
150.degree. F.), the biasing member 48 and the piston member 50
move from the second position back to the third position. This
movement decreases the size of the dispensing chamber 52 causing
the pressure to increase within the dispensing chamber (FIG. 6).
When the pressure exceeds a predetermined threshold, the valve 56
opens allowing the additive material 64 to flow along a second flow
path via the valve 56 where it exits the shell 52 and the additive
cartridge 20. Thus, for each heating cycle of the engine, one
metered amount of additive material will be added to the engine
oil.
[0037] Referring now to FIG. 7, an embodiment is shown of another
additive cartridge 20. In this embodiment, the metering device 42
includes a first biasing member 64 coupled to a first piston member
66 arranged within the interior area 46. Also disposed within the
interior area 46 is a second biasing member 68 and a second piston
member 70. The biasing members 64, 68 are made from a shape memory
material, such as but not limited to a Cu--Zn--Al--Ni alloy, a
Cu--Al--Ni alloy and a Ni--Ti alloy for example. The piston members
66, 70 are disposed in an opposing arrangement within the interior
area 46. A dispensing chamber 72 is defined between the piston
members 66, 70. The valves 54, 56 provide a flow path into and out
of the dispensing chamber respectively.
[0038] The embodiment of FIG. 7 operates substantially similar to
that described above. The biasing members are responsive to changes
in temperature to move piston members 66, 70 between a first
position and a second position when temperature thresholds are
reached. When the additive cartridge 20 is cooled below a lower
temperature threshold (e.g. <130.degree. F.), the biasing
members 64, 68 contract causing the additive material 62 to flow
into and substantially fill the dispensing chamber 72. When the
temperature of the additive cartridge 20 is increased above an
upper temperature threshold, the biasing members 64, 68 expand
moving the piston members 66, 70 toward each other and causing an
increase in the pressure within the dispensing chamber 72. Once the
pressure increases beyond a threshold, the valve 56 opens allowing
the additive material to flow out of the additive cartridge 20.
[0039] In other embodiments, it is contemplated that the metering
device 42 may be constructed with two biasing members acting on a
single piston member. In one embodiment, a second biasing member
may be disposed within the dispensing chamber. The second biasing
member could be made from a shape memory that expands when cooled
(pushing on the piston member) and contracts when heated. Thus the
two biasing members would cooperate to act upon the single piston
member to draw and disperse the additive material. In yet another
embodiment, a second biasing member could be co-wound together.
[0040] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
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